SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '216564f5b7a498abd6a44d89acff9918bfb680a1bfbdd26064a38aae75401828' 
  AND token = 'iivOvLVfElZaRN6T7KN1cN2neyRni93/iw0YJHGaugs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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