SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fee19f5c16e1e464a49e1049f06a46532495cc78e035feed7e7fc573a620c8d1' 
  AND token = 'kCKpl1U5ucHkzLvc7m4bYK4F1nFJvTDzbOQgw9j/NV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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