SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e492c5e17a51e84cecc6ff69fdc250414c78e8225601d2afc34bbea216405ce5' 
  AND token = '6FsOeg6AcMeScNjAkzIK7rsUORAcXfYGloeVEfeUo3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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