SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74e315c43926e12c91bd669c208c73791a2b9f861d8fa5e783b8f897cf9fc3db' 
  AND token = 'qlIRLLnAJtNoOhhnnxbTQ/v0DjhyGtf4FW5oSmBZXVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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