SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a182b7e71622f53417461b1961a5802cc5e48a31f036d44c4975aa62ca59431f' 
  AND token = 'vsxDS1GXMIgbk94FWCpGeZF+LDXoteTif5felhpJp88=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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