SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '656bf9a8e053460521e8b4b8fab2243f1025bb94989e39867f455624661b1970' 
  AND token = 'vPvBcowzBHB2J+2KkRRJXB8m2AkKXoTy+/SS4ltsfzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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