SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78a787f36d92a603ae33b93dca0bc45609f96e785cafb3f854085b56c75ff8a7' 
  AND token = 'qDW9w3VDLjndP4JKbt/VDY1csDoUF9aG2sFOKvgo8Ts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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