SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f0ecb04af31765ec4f8675c898d4e815d58d1379b6708c66848247071f6140a' 
  AND token = 'P+H7gGkkKFZh+CYJmbq8uZCmzv88xxHuerfbs/Tqx78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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