SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '12d5e5bf007d445114beda881793a647eed1ac6403d2472278b76e7f4b66b521' 
  AND token = 'Q12H6du+wivKLY8IVx/cvV1zsYQXo0sUjr4Fd/ozzvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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