SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f53093ded4b8470239fdfbe0a8b27cab3d39cb30db147b39ad09e59d2ad4fa5c' 
  AND token = 'u2fRmGP7aFnDIV1Q80h5q5OObpDCFhMXkx+q7l+n2TY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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