SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb8f228d5259f3f689dd5936ff642e874dcd44181c01946c307a2a9721d20f75' 
  AND token = 'wfqERmzWF01ipXLYSzeqh8o4sCG93brTq7Bo0VdHgZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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