SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f93759caa2bd5fde9853b09b2f17960675cae9f86662128fe77f7b0755ea67a' 
  AND token = 'hOuEcsLGPLwqQxZH8Mn9Oy1Jjy2GMNJXLRBOxNJBdlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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