SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf65599fd0b9b2c1cbe559a0f5afc57a64e685f2d9180b31c2abcb20be2e7f46' 
  AND token = 'gcsu93ch7LSS7tFfDUSU+DyZf96Q06+E5EhGYz0K4R8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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