SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29e33076fc795fcfac871461f2e7738187e81cba6808bbfae032a1b8133b57aa' 
  AND token = 'C5B8yjsnUkqo6SbFIX5pKnkeG8PNKwy1q4nDDWlEhww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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