SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '956eea4849008b716fdbe89dda24dc334229f4fe76777b9ac936a1a99df869a2' 
  AND token = 't4HlZ5w/BjusbvPy1bCh2MQmgGPa8xxG/habRdeeQO0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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