SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c73b04a3a0b40404c45a5457d80aec8456d187cc806a41bfd806661a2669695a' 
  AND token = 'oZnsb7HYleS46JgUfHuo0o4RN+Qw+UDgnelcWp5quFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}