SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8ac3a15c83e44ce76ce388e725999551b8cd3440c545945981c7130025b958f' 
  AND token = 'nYSbiNkDeCs0zaqVPRD/aIDdOWtLuc1CeECTC8CuUzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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