SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d0d529ca2f293f71d5bcb2b0151159374f5d8c256bd810ebeb294cc38edc0f8' 
  AND token = 'ta3uFdlw8Z6RYLroEqh7+nv/4Y2VU9rzGpUw/lzjP6U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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