SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b43e8680819ab9a93b63f6b2beb06f1dfd9ea927d6c4ba9318536404dc75ac0' 
  AND token = 'Rj/lc2jIm8WMZueh/QxpqcJeC9vJtwPWm1YW1/hKRMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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