SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f3042fe8551db34e5d93a01672399d0e73520d715c857475f37348c20eb98898' 
  AND token = 'AUObih9/Z3rB4ka8VauURjWLc2nhZayjMAYssMlHDv0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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