SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2c58f9ba7250044fce630b8049dbfbdd19b0bb69935a289e7bdc6b3b71b9ea0' 
  AND token = 'klb3EP4PEcBfMoIWJwqzavYMP3a9U4wHbcRRg/hYIno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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