SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec9267f05eb098054f60ced58c8cd3c51a34328293f40dd02f36806339230590' 
  AND token = '+VUJvmUTiIxz2PR5AZ3kBYMV7pEZ2ohlSnOlNedHmdg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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