SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '950a71b7b45df091ef09f91090c355c5566a01c54b4eee5cf9aedec37c943cac' 
  AND token = 'zWT3NdFUPCpT4CRP0oAwsu72TrAa1uqz8M1Wp3bnDNg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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