SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45ebee3c547bc6f5ebbe7f5c1c881a8e26758964c9db6b60e4890cbc9d7d1a6' 
  AND token = '/PUa5sX3jbzTPW9KMSpWrRAH923OVwdUReH82RRZNgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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