SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f50810a32eb41944a0f883298749c333bf30248cfb7228e43af0a606b16f11d4' 
  AND token = 'tmUXh0wKyk+k2KYMqMTCU2XsEGf8xYCenbXeV4Z3OVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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