SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '842416380d8c84b213e817cb76ff4ad588e440b4ac150e97819e6156e4d1a33d' 
  AND token = '2gAdKa8CpSi9zPrSAWvXSNt6Q1EoBNCMCcj0ZZrfdYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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