SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644ee189281184a3e51438679d854328fa1ca0a6849369fdc091142e302fc2e8' 
  AND token = 'h7v9K+fw6Cz2GxSxHMzKVaQsyO8/P+RXQbTnWEl3In4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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