SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8036bcd31327984b2070532101fb46c3eea609e32e718f8ca9e8607f9517ade6' 
  AND token = '3qvtrZtLvjDjhs08iw3KYf9XKWCWEk+xKuzRsPQy3B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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