SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f38beec4222f3d19dce4a253c7820f74ea82e3ee89db867a2f769755f101cfd6' 
  AND token = 'biRIR0uAxP8ZYsiGXH1olQ1mibYUlGpD+MsEhxtLlIs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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