SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8936b611b2400d4c5aac215b9a18bfdb218f9e426ab0a17a75e93928420e706' 
  AND token = 'yOpY+yA+8r+GDgGQa3cmaGo+9tbLccA5cny5VgUhBCQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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