SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5349024cc592f150fa365b7eb7a91f6f894d04801b2fce73e5c398bbf4dafbe5' 
  AND token = 'mjYLWHKtwk/+DTGkmXPEB80Lxd6Nl7ubbCVM/SZzY6E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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