SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd914661eb264fc0f81aa849e1a0e0bdc255c1f7497d3b64de5b6c001634bc49' 
  AND token = '8iCPdRl2+6TVOibg/cVwpJnQfUe4COXEhhJFcmV7+mE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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