SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d0867fb86319babb5f1e5dd8bbc05b6706f848634dfd4609d3e8ad7e0f69b42' 
  AND token = 'lMq/uYW6gW9JN6Kwv2RMup/jHiIjgjgSFqRQsPDdubs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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