SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6f855f4286211e942300e97c3aef6733bd5f175371a7ec4c3485ee11e92f8d4' 
  AND token = 'o8Wl0n3rI8nI3fkeP+lyjM3PTS+heFgo0WV/9bBSnuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}