SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f414c326680845a29ca366f88402159489c8292bbb196454d6e686ea8334ced' 
  AND token = '+6RXSPPsUSKIOAzkbJO3G6xkbibOIYGxVMY+bkNNXCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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