SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b74a1495d5e36786096a5b847e4f37fd8086d4fea074fd9b46b4532f1d182b98' 
  AND token = 'YZNy3Ktn17O8HJGJx1/CapjsvCyULOKTwwbvISJQzKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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