SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c6ffc72e88e7ae57117d5d85702b1ff8d9c548f521e5250ca5c6b94bf8b0af9' 
  AND token = '4OiweADTS3DuAVf/tASZ31SYxSXJJnGMSKN0s0nUCt8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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