SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '799d595fd2e2c5e4aa5eb0132d2ed3c919b685406b46a9abaaeb82be0cd26cd2' 
  AND token = 'sBYaw8EbE/4PgH5LkZaCghiop9HvTwkOI6AeY9Lrhj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}