SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '683b935b033ab0caf48cabdc0d1a135e1cf300a035fa3f63fa4d027c4aba36d0' 
  AND token = 'JgILG+oWlKJVauG2i+t9ySnj7HkQ6/n3KJyfzc9iJ7o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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