SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38ef92b1d579a8d561756b7b73892dc54eef26a16b9f5e53472a80958fcbf086' 
  AND token = 'KiCfMOmysAwJrURstiPUwfzNDXoGmmhxWpU+hzQEbA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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