SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63e76183c908258dad606984b67f1daae15f3a12cdedcd5b6a2418099c31866c' 
  AND token = 'RSfWEmM19e3JRAwF1VcamksTpUqwBddz7v1SYo6emNE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}