SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2602f7d1999a8b1626ade408b311c9ebdf06b7c656e8266e87cd72d020fb131' 
  AND token = 'bS8x+qKeP0bLDMuRLqE7c+VJyLgGetIHFLqeKVfUreg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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