SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4670e8eddf3dc720669f892bf0fbacd071664f5d50903bf7795affed65bfa281' 
  AND token = 'ZVAtQCAKl0h9Mg49fTqbLZzqO+Vb3e5N4eibWD0rBEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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