SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a52b23e461d673aaa6bafec06e90d9ab6f42799ebc54739b8afbc89ea1289ec3' 
  AND token = 'SATj1jJvwTnaMPVQLaRPKAxVVS6CkzJQp4OEw7hiDTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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