SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29878ce5d6ab8db960def539a00f14fd4f574fc1fab65994120a6e776ebc3058' 
  AND token = 'SIn+eotlRyzYTgqzl7fF2jh4pghh47OOA1mlGBrt3i8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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