SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '989b036220069f8831a2093bdb6cd368a00d8f2e1fa3de55fcb63e73b9c439f8' 
  AND token = 'RPD5vpm0KF6Njj8WDANZstpBxwzudjzgNSN3miQiTts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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