SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f37ac03d987e4faf4e569773b159f47ae5ff8c1b3225f8e8d5c6cdee8a6cbced' 
  AND token = '/jsbMR6h0WIEw8KpG60DIwzdu0TZ87GavGsFRHUVqiU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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