SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6162b873ca1f8eaced68db9c72307e5593023815ac744696ca48faa514aeb90d' 
  AND token = 'stfvf6OOER3dbWSExJU1X/JiaOsc2UMxejqcX/mxmpg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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