SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e2753de8c2a745e89785f5686703f15f47188792edb14802233715aa0363a86' 
  AND token = 'cXDhmmTA3pPLqoGEqnxfbiBq1Y4gsmIVclzHnTGiej8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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