SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b10ee564eb49e9d281a28a9575d866f78236aef77f055c55341a171705fa9334' 
  AND token = 'h8ipIjjeU+Bw7sN0Hbxw8F0xC3AXvWOK8kZNFxNi1nU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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