SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2d7487036789a7187f744c708e0ebd32ee83618fc5270cf58fd830cee9922767' 
  AND token = 'R30Z27sKVynWrscFsScy3Qti3x2k4LsDWR7zKEN6ZIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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