SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '694ca77a340cec9ee30aa1dafc79dc03005d0c49d0658e200579f63a45877a2e' 
  AND token = 'b79eYtQYAyEMnAkdjbYg8J11ex4Ey66tlMaJItyvCvs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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