SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45be69b590d302d7612d007d421687ee917e2489d695fcd0ac2eb906ce6e0452' 
  AND token = '5Qbmwk2C8lAPyLwYfIGLJERzV7MSlADhjVuwcC1n9Oc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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