SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ddc316a1088e96a651521c7fdf2335bc475f2277c5555feecef851735f8453c' 
  AND token = 'mW1NYwrpg9dtNLFv4kN2oUSVjmbOUKHrie+KaZdjLpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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