SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94260b410cb2dd2aea849bd6ce2d10d75664a7b01c5c1794a2562e4ccfd46141' 
  AND token = 'fKiLiAcZ0NwlYJUMRhKhTLVKsb8oQIGBO0OL3gnIfdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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