SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c515273648f466d4b7b430133863626a824bd2abbadb506a05035bd2bb25691c' 
  AND token = '88z2BPXYteOfVQPRhxAcrzskLjYDjH60JpWnBpSyHIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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