SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0b2b655be472b6ae55461e9876b7d7a580cea4776e218a9fc20413e390b410c' 
  AND token = 'WNkCed+ypgYWnrSN2aSQ9fdDPGSSDuOQxieNHHf8Y2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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