SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c4d9fa8ef31e982dc1e2d9c37037f2d4bf7061b3b3d9fe05f1aa504f3bda004' 
  AND token = 'u/RJRbwnmb2cdjPdVHRwm13M2S/mEXbT+/dX8ItJV0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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