SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '778dbed20c424079c7f21941c46c9184eb2f9f7146e668638f768839fad9d9e3' 
  AND token = 'HPCZP5yZC9UmuPnjGcu2oVRKvRA8kMssTLR8X1QAVw4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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