SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f15ac7412dcbbf230ec1b2842025ba3855485a0dbbdb2d73a57edb6e0f9abf7a' 
  AND token = 'ZHW24pkHj312kW1VM5ZDtVxsYT94CQqc9i7iDOTfUec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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