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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '938beb7606e2b6b90b5b4ea4bbc318f0297dab29daba18ec3c9f9ca30ac34ff8' 
  AND token = 'JxQaU9oNhzEjOj3ePNRP2LXhOpfZhiEBfKu5NCS8vqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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