SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '163fc6e3598264b4709bc299bac9810cb46d2139b6bcd30d35d6d29b32934d27' 
  AND token = 'AyMfqg/FpIDM47xlloHPgT3ffpVooooxiLqPXAq3OC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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