SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd173ec49d386815f0c1bd2d9dd46d2ef3b47076529a61484b963255747a8103c' 
  AND token = 'm/5nh5ANC7nPVG2Y8SuXZYaA04AqnsPCCQpFIkw+kM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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