SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49c6252019f743822d2125bf1a61858932c01f49eea53396a26e5f2ee62a03d2' 
  AND token = '7UMN97Izy4YP6B1OAbbvjRm6mK9iIFwoKzWBiR4jblU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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