SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c4b4f27240464a1bbdd5e31de90e0aab97c2138af2fc456a3e55793ac5d243fc' 
  AND token = '98+ghrpx1/lLpAD7txW+TdNwwA1wetsTTAakkHItw7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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