SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '709a081c0aa2b0c035e1c55ae0dbba0fd0ff7674ec98ce6efccbbd502f82a2f5' 
  AND token = 'L4kEaCm7R0jEPW+xjlHSB81cjgROQUH25fPxRh+MT/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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