SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '740520c1df6cefc5aae92f74751971fc14466eeb021e4e83cc2998021df8fba1' 
  AND token = 'vkwGLr/LreubYS5v+zanAmY70XRLDLFBZ+HYlQSVxxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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