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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a7fe78aec895720285e19dc79c6c1a63898dfe8e7c1b084f3ae1ae6ce138ea0c' 
  AND token = 'a8Er0h/GrmGyO8tLgsE+TWx+Wx2lSofw0y7SgdSWgk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}