SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'a23b28c74b5aa68e52678b14eb613929b6e8675d017886b033e9766710a918b9' 
  AND token = '/gGPKMa64SeB3CJZBQ8sATRLq5FVFX5zTe7HhKgJDL4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}