SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '560e7f18f5261f7257861674ab33be759ffd9f7f121f568054db0489325e0389' 
  AND token = 'ObKpDxTCWZ7gvMnr3gmG4GCzMGDSIj2ks8iESQJqzlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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