SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c5dc0177ea3d4eb6ced6ac3e01073aab42675a56660bde6978a450385a967f2' 
  AND token = 'vJXj8KdPx+DBnTzLWAV+mGqduy3DiyVxp8U16q3S2jQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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