SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b03fe9de205be8f2b288187a66ecee72753b76398d44b858454eeb7475d71b8' 
  AND token = 'ty+HIGpTxPuutBiTDrQd9szN1RHNhvfUEou8WDgHJAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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