SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da1538073e55be44be960c044267d3ecb73be35eea31e15a31e4007e615638a1' 
  AND token = 'f6SlD2onTQIdNrYmkkkXHhcOxlCQgDMwXCBS4ccpmE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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