SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8c8af66ff471f1375abc47444e8c6e02037b0783aba26bdb52d97430ec4eab1' 
  AND token = 'ew3q2vB227aJaT+ethwYBvzGAgcw6y2wmnmJb9XxIPY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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